using System;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Runtime.InteropServices;
using System.Windows.Controls;
using GhostNET;

namespace ghostnet_wpf_example
{
	public partial class MainWindow
	{
		/* Filter so we get the first non-full res and the last
		 * full res */
		private void PageRangeRender(int first_page, int last_page)
		{
			if (m_viewer_state != ViewerState_t.DOC_OPEN)
				return;

			int real_first_page = -1;
			int real_last_page = -1;

			for (int k = first_page; k <= last_page; k++)
			{
				if (real_first_page == -1 && ((m_docPages[k].Content != Page_Content_t.FULL_RESOLUTION) ||
					(m_docPages[k].AA != m_aa)))
				{
					real_first_page = k;
				}
				if (m_docPages[k].Content != Page_Content_t.FULL_RESOLUTION || m_docPages[k].AA != m_aa)
				{
					real_last_page = k;
				}
			}

			if (real_first_page == -1)
				return;

			m_viewer_state = ViewerState_t.BUSY_RENDER;
			m_ghostscript.gsDisplayDeviceRunFile(m_currfile, m_doczoom, m_aa, real_first_page + 1, real_last_page + 1);
		}

		/* Callback from ghostscript with the rendered image. */
		private void MainPageCallback(int width, int height, int raster, double zoom_in,
			int page_num, IntPtr data)
		{
			Byte[] bitmap = new byte[raster * height];
			idata_t image_data = new idata_t();

			Marshal.Copy(data, bitmap, 0, raster * height);

			image_data.bitmap = bitmap;
			image_data.page_num = page_num;
			image_data.width = width;
			image_data.height = height;
			image_data.raster = raster;
			image_data.zoom = zoom_in;
			m_images_rendered.Add(image_data);

			/* Dispatch progress bar update on UI thread */
			System.Windows.Application.Current.Dispatcher.BeginInvoke(System.Windows.Threading.DispatcherPriority.Send, new Action(() =>
			{
				m_page_progress_count += 1;
				xaml_RenderProgress.Value = ((double)m_page_progress_count / (double) m_numpages) * 100.0;
			}));
		}

		/* Done rendering. Update the pages with the new raster information if needed */
		private void RenderingDone()
		{
			for (int k = 0; k < m_images_rendered.Count; k++)
			{
				DocPage doc_page = m_docPages[m_images_rendered[k].page_num - 1];

				if (doc_page.Content != Page_Content_t.FULL_RESOLUTION ||
					doc_page.AA != m_aa)
				{
					doc_page.Width = m_images_rendered[k].width;
					doc_page.Height = m_images_rendered[k].height;
					doc_page.Content = Page_Content_t.FULL_RESOLUTION;

					doc_page.Zoom = m_doczoom;
					doc_page.AA = m_aa;
					doc_page.BitMap = BitmapSource.Create(doc_page.Width, doc_page.Height,
						72, 72, PixelFormats.Bgr24, BitmapPalettes.Halftone256, m_images_rendered[k].bitmap, m_images_rendered[k].raster);
				}
			}

			xaml_ProgressGrid.Visibility = System.Windows.Visibility.Collapsed;
			xaml_RenderProgress.Value = 0;
			m_images_rendered.Clear();
			m_viewer_state = ViewerState_t.DOC_OPEN;
		}

		private Tuple<int, int> GetVisiblePages()
		{
			/* First child of list view */
			Decorator border = VisualTreeHelper.GetChild(xaml_PageList, 0) as Decorator;

			// Get scrollviewer
			ScrollViewer scrollViewer = border.Child as ScrollViewer;

			double top_window = scrollViewer.VerticalOffset;
			double bottom_window = top_window + scrollViewer.ViewportHeight;
			int first_page = -1;
			int last_page = -1;

			if (top_window > m_toppage_pos[m_numpages - 1])
			{
				first_page = m_numpages - 1;
				last_page = first_page;
			}
			else
			{
				for (int k = 0; k < (m_toppage_pos.Count - 1); k++)
				{
					if (top_window <= m_toppage_pos[k + 1] && bottom_window >= m_toppage_pos[k])
					{
						if (first_page == -1)
						{
							first_page = k;
							last_page = k;
						}
						else
						{
							last_page = k;
							break;
						}
					}
					else
					{
						if (first_page != -1)
						{
							last_page = first_page;
							break;
						}
					}
				}
			}


			return new Tuple<int, int>(first_page, last_page);
		}

		/* Render only visible pages. Used for single page formats as well
		 * as PDF (and ideally XPS) where the interpreter can interpret only
		 * specified pages */
		private void RenderMainRange()
		{
			if (m_viewer_state == ViewerState_t.OPENING)
			{
				m_doczoom = 1.0;
				xaml_Zoomsize.Text = "100";
				m_ghostscript.gsPageRenderedMain += new ghostsharp.gsCallBackPageRenderedMain(gsPageRendered);
			}

			m_viewer_state = ViewerState_t.BUSY_RENDER;
			(int first_page, int last_page) = GetVisiblePages();
			m_ghostscript.gsDisplayDeviceRunFile(m_currfile, m_doczoom, m_aa, first_page + 1, last_page + 1);
		}

		/* Render all pages full resolution. Used for single page files as
		 * well as documents like PostScript and PCL that are not page
		 * based indexed */
		private void RenderMainAll()
		{
			xaml_RenderProgress.Value = 0;
			xaml_ProgressGrid.Visibility = System.Windows.Visibility.Visible;
			m_page_progress_count = 0;
			xaml_RenderProgressText.Text = "Rendering";
			if (m_viewer_state == ViewerState_t.OPENING)
			{
				m_doczoom = 1.0;
				xaml_Zoomsize.Text = "100";
				m_ghostscript.gsPageRenderedMain += new ghostsharp.gsCallBackPageRenderedMain(gsPageRendered);
			}

			m_viewer_state = ViewerState_t.BUSY_RENDER;
			m_ghostscript.gsDisplayDeviceRunFile(m_currfile, m_doczoom, m_aa, -1, -1);
		}

		/* Called via zoom or aa changes */
		private void RenderMain()
		{
			if (m_viewer_state != ViewerState_t.DOC_OPEN)
				return;

			if (m_doc_type_has_page_access)
				RenderMainRange();
			else
				RenderMainAll();
		}
	}
}